1. Field of the Invention
The invention pertains to the field of fluid dispensers. More particularly, the invention pertains to beverage dispensing machines having temperature regulation of the dispensed product.
2. Description of Related Art
In most aspects of our life, each individual person has his or her own preferences. For example, people prefer different kind of food, different kind of spices in food and so on. This is also true when it comes to coffeexe2x80x94each person likes to drink his coffee at a different temperature. Especially in fast food restaurants and coffee shops, the temperature of the coffee that is sold is most often very hot, much too hot for most people to drink. So each person has to wait until his coffee will cool to his or her desired temperature, which might take 10 to 20 minutes. This become very irritating, especially when you want to drink your coffee right away and the only way to do it is by small sips, and even then you will burn your tongue. Since we have the free choice to buy our food according to our preference, why not the temperature of our coffee?
Industrial coffee machines typically have two main parts: a brewer and a container where the coffee is stored. Normally, for best results coffee is brewed at a temperature of near or just below boilingxe2x80x94about 200xc2x0-210xc2x0 F. Then, the coffee is stored at a reduced temperature, so as not to cause the flavor to deteriorate too badly. The coffee temperature in the storing container is maintained at about 180xc2x0 F. or more by a regulated or continuous heater or an outside heat plate.
Thus, the temperature of the coffee that is served is about 180xc2x0 F., which is too hot to drinkxe2x80x94for most people a drinkable coffee temperature is between 130xc2x0 to 150xc2x0 F. In fast food restaurants the coffee is served in paper cups, the paper material of the cup is a good heat insulator and has very small heat capacity. Therefore it takes quite a long time until the coffee cools down to the desired drinkable temperature for each individual. Since the customer does not know what is the coffee temperature he will probe the coffee temperature by taking small sips.
By doing so he might burn his tongue and the inside of his mouth. Also many customers would like to drink their coffee right away with their food and not have to wait until the coffee will cool to the desired temperature. One study showed that while coffee shops tend to serve coffee between 168xc2x0 F. and 187xc2x0 F., but a survey of 225 consumers showed the largest group preferred their coffee at 140xc2x0 F. or 160xc2x0 F. (O""Mahoney, et al, xe2x80x9cAt What Temperature Should You Serve Coffee?xe2x80x9d, 1999 Annual Meeting of the Institute of Food Technologies, Report 50B-1).
There have been a number of U.S. patents covering devices for dispensing beverages, especially coffee or tea, at different temperatures.
Cornelius, U.S. Pat. No. 3,634,107, xe2x80x9cApparatus for Dispensing Coffee Beveragexe2x80x9d (1972) is a vending machine which stores carbonate coffee concentrate at ambient temperature (or refrigerated non-carbonated concentrate). On a vending request, it mixes a selected volume of the coffee concentrate with cold and hot water to dispense coffee at a selected temperature and concentration. Unlike the present invention, Cornelius"" vending machine does not dispense fresh coffee, and requires maintenance of volumes of water and coffee concentrate at various temperatures.
In Haynes, U.S. Pat. No. 4,550,651, xe2x80x9cBatch-brewing Coffee Systemxe2x80x9d (1985), coffee is brewed in batches, and stored at reduced temperature in a holding tank. When a cup is desired, the brewed coffee is heated by passage through a heat exchanger in a heating tank. The Haynes device cannot set a specific temperature for each cup of coffee.
In Verheijen, U.S. Pat. No. 4,791,860, xe2x80x9cEquipment for Supplying Hot Waterxe2x80x9d (1988), the user sets temperature of water desired for beverage. The temperature is controlled by passing water through flow-through heater for specific time, then turning off heater or bypassing heater, so cold water is dispensed for specific time, mixing to produce water of selected temperature. Verheijn does not provide brewed coffee, but rather water of a selected temperature, and requires complicated flow-through heaters, mixing valves, and timing circuitry.
Kerner et al, U.S. Pat. No. 4,792,059, xe2x80x9cSelected Hot, Cold and Room Temperature Pure Water Dispenserxe2x80x9d (1988) is a water dispenser which contains hot and cold reservoirs fed from holding tank. Three valves control water dispensed, so the user has a choice of hot, cold or water at something between room temperature and tap temperature, but cannot select a specific temperature of the water. Kerner does not brew coffee or other beverages, but is simply an office water cooler/heater which can dispense water at three temperatures.
Anson, et al, and Anson patents, assigned to the well-known industrial and office coffee-maker manufacturer Bunn-o-Matic, (U.S. Pat. Nos. 4,920,871, 5,584,229, and 5,858,437) all provide coffee brewers which can brew a beverage at the normal 200xc2x0 F. temperature, but dispense it into a carafe at a reduced temperature, where it is presumably kept at the lower temperature for pouring into customers"" cups. Anson""s machines use a two-part brewing funnel which has a bypass channel for colder water. The hot brewing water goes through the coffee grounds or tea leaves in the center of the basket or funnel, and mix with the colder water in the bypass channel. Anson cannot vary the temperature of each cup of coffee (the customer""s coffee is poured at whatever temperature the carafe is kept at), and the cooler the desired temperature, the more dilute the beverage as more cold water is mixed with the brew output.
Usherovich, U.S. Pat. No. 5,724,883, xe2x80x9cHot/Cold Beverage Brewing Devicexe2x80x9d (1998) is a home-type coffee or tea maker which, in addition to the conventional coffee brewing mechanism, has a second carafe which can store the brewed beverage at a lower temperature by passing the hot beverage through an exchanger with a cooling medium, and then diluting the hot concentrate with cold water. There is no option for dispensing a cup of brewed beverage at a specific temperature, and, as a dilution system, the lower the temperature to be dispensed, the weaker the beverage.
The present invention dispenses hot coffee or other beverage by the cup at a selected temperature, which can be varied from cup-to-cup. The beverage is brewed in a conventional way, and in one embodiment is stored in a conventional holding tank at elevated temperature. The holding tank communicates with two smaller reservoirs. A quantity of beverage is stored in a first reservoir at an elevated temperature, at or above the maximum desired dispensing temperature. A second quantity of beverage is cooled and stored in a second reservoir at a lower temperature, at or below the minimum desired dispensing temperature. When a cup of beverage is to be dispensed, the temperature is selected, and a quantity of beverage is dispensed from each of the reservoirs, proportioned so that the resulting dispensed beverage is at the selected temperature. In another embodiment, the first reservoir is omitted, and beverage from the holding tank provides the elevated temperature beverage for mixing.
In the present invention the original but colder coffee is mixed with the original but hotter coffee to adjust the coffee temperature to the desired one. Because of this we preserve the coffee quality by not changing the strength or the taste of the coffee, only its temperature. This is superior to those systems which use cold water, diluting the coffee strength and changing its taste.
In the present invention the cold and the hot reservoirs are refilled automatically from the main holding tank. Therefore the system requires only one single mixing valve to control the coffee temperature, making the present system simpler and more reliable. The simple system of the invention also allows much more accurate control of temperature than the reheat or dilution systems.
The system of the invention can serve single users where each patron can choose and receive coffee at different temperature. In addition he will receive the coffee at the chosen temperature independent of the quantity he is pouring out.
In one embodiment, the system of the invention can be directly added to existing commercial coffee makers without making any changes to the coffee makers, improving the quality and the taste of the coffee because:
the coffee can be brewed at the optimal temperature to get the best coffeexe2x80x94about 200xc2x0 F. Today, most coffee makers have a brewing temperature around 180xc2x0 F. because of safety concerns.
in the two-reservoir plus holding tank embodiment of the invention, the coffee in the holding tank can be stored at lower temperature which will extend the time that the coffee can stand without loosing its quality. This is possible because in our system the coffee temperature that is poured out is independent on the coffee temperature in the holding tank.
Adding the system of the invention to existing coffee makers will eliminate the need of a heater or external hot plate used to keep the coffee in the holding tank at high temperature (180xc2x0 F.). Instead only the small amount (5 to10%) in the hot reservoir of the system has to be that hot. This will lower the cost of operating the coffee maker.